Device for stereo-reproduction of sound registered on cinematograph films



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Jan. 10 1961 R u PERELLO 2,967,912 DEVICE FOR STEREO-REPRODUCTION OF SOUND REGISTERED ON CINEMATOGRAPH FILMS Fil ed Feb. 25, I957 P/;ofo E/ec. (q/ls In pm 00) pm e Pr ojecf0r Fllm Sound Eic/r- Relays Lighf Source P V 3 Sou/m Amplifier I PU of Film. 0, pg

E5 Speake rs IN VENTOR RAMON UBEDA PERELLO WWU W uromvsr United States Patent DEVICE FOR STEREO-REPRODUCTION OF SOUND REGISTERED ON CINEMATOGRAPH FILMS Ramon Ubeda Perello, Buenos Aires, Argentina, assignmto Ivan Ibaiiez, Buenos Aires, Argentina Filed Feb. 25, 1957, Ser. No. 642,042

4 Claims. (Cl. 179-1003) The present invention relates to the distribution, or rendering stereo-audible, the sound effects registered on a cinematograph film.

With this invention some, at least, of the many defects from which the most generally used system sufiers are overcome.

This most generally used system of stereo-audible sound reproduction makes use of four electro-magnetic sound bands, corresponding to sounds originated at the front, back, left or right sides of the stage.

As the standard width of the film is 35 mm. and cannot be altered at this time, the four registered sound bands have to be fitted into the available spaces between the edges of the pictures and the edges of the film itself, and, to be able to do this, it was found necessary to reduce the actual width of the sprocket perforations and that of the sprocket teeth on the sprocket wheels.

These thin and sharp sprocket teeth rapidly damaged and wore out the films, whose useful life was materially shortened thereby.

The system of the present invention not only uses the normal, single photographic sound band, but also avoids the necessity of having four magnetophonic sound tracks, with all the consequent additional laboratory work of transferring the sound to each separate positive copy individually.

There are other, important defects that should be men tioned when reviewing the most generally used fourdimensional sound reproducing track system, principally the cost, which is considerable, and furthermore the fact that four-separate magnetic pick-ups are required, each one having its own outfit of amplifying valves and group of loud-speakers.

The present invention eliminates all the above mentioned defects, not only as regards heavy original outlay, but also the additional laboratory Work and the damage resulting from any but the standard sized sprocket teeth.

One of the most important advantages arising out of the present invention is that of obtaining the register of sound on one, single band on the negative instead of in four bands, and this method of stereo-audibility can be applied to any existing negative film carrying a single sound track.

The normal life of the positive copies of films obtained by this invention follows as a matter of course, as they require no additional magnetic sound tracks. The use of four amplifiers, each one with its corresponding pick-up is eliminated, as this invention requires only one pick-up, one amplifier outfit, whilst the film perforations and the sprocket teeth remain standard and the result is equal to that of the most costly and complicated four track system, reproducing the sound stereo-audibly with all the desirable perspective and outstanding effects expected from modern cinematographic. projection.

This magnificent result has been arrived at by the invention of a selector device that can be adapted to any type of cinematographic projector, including those for 16 mm. films, the device being operated by means of 2,967,912 Patented Jan. 10, 1961 signals previously imprinted on the positive copy of the film, said signals, according to the particular position where the sound was originated, control and direct the reproduced sound after the current carrying same has passed through a single amplifier unit, to the particular loud-speaker or bank of loud-speakers placed at suitable positions in the auditorium.

in accordance with the present invention the above mentioned signals are produced on the positive film in consequence of specially placed signal markers previously fixed in the transparent spaces of the negative, between pictures. 4

These transparent spaces consist of a broad white line in the negative and therefore appear black in the positive copies.

The accompanying drawing is a diagrammatic view illustrating the arrangement of the picture strip and showing the manner in which the different control circuits are connected to the photo-electric cells to close one or more circuits through the sound amplifier and a pre-selected speaker when one or more of the photo-electric cells is energized.

In the drawing and more in detail, there is shown a portion or section of a positive cinematograph film I having transparent signal areas 2 arranged in accordance with the present invention. The position of the transparent signal areas 2 are arranged at selected points of the opaque band 3 which is arranged between the picture frames as shown in the drawing. The picture strip 1 is provided with spaced apart perforations la along the 'rnarginal edges thereof to facilitate feeding the picture strip by the conventional feed sprockets in the picture projector (not shown).

The picture strip 1 is trained over a hollow sprocket wheel 10 rotatably mounted in the picture projector and is guided by suitable rollers 10a likewise journaled in the frame structure of the projector. Mounted within the hollow sprocket wheel 10 is a plurality of light sources 11 arranged in spaced apart relation corresponding to the spacing of the transparent portions 2 on the opaque strips 3 on the picture film. The sprocket wheel 10 is provided with a plurality of properly located slitted openings to permit the passage of light from said light sources through the transparent signal area 2. The openings are indicated by the dotted lines and are arranged to register with the transparent portions 2 in the bands 3.

With the positive film 1 threaded through the projector and trained over the sprocket wheel 10 so that the black spaces between the frames in the positive film correspond and coincide with the slitted openings in the sprocket wheel 10 it will be readily observed that rays from the light sources 11 will be projected through the openings 2. Mounted adjacent the sprocket drum 10 is a series of light-tight receptacles 12 each containing individually iso- I lated photoelectric cells with each photo-cell spaced apart a distance corresponding to the spacing of the transparent portions 2 in the opaque portion '3 of the film. Each receptacle 12 is provided with a plurality of window openings arranged at right angles to the slitted openings in the sprocket drum, one of said window openings corresponding in position to each photo-electric cell and arranged so that the light from one of the sources 10 inside the hollow sprocket drum can pass through one of the slitted openings therein and through a transparent area 2 of the black band separating the picture frames in the positive film. When the ray of light penetrates the window opening in the casing of the corresponding photo-electric cell 12 preselected by the particular position on the positive film of the transparent area 2 which resulted from the position of the opaque signal affixed to the negative the corresponding photo-cell 12 will be energized.

excited or energized by the ray of light from one of the light sources 11 falling upon it actuates one of the selector relays S with which it is connected, and this particular relay in turn energizes a corresponding power relay which controls a switch so that a circuit will be completed from the sound amplifier through one of the corresponding loud speaker units 5 to 8 inclusive. -As shown in the drawing a bank of loud speakers are indicated with the left and right hand loud speakers 5 and 6, a center loud speaker 7 and a back stage loud speaker 8 are shown and these are arranged and adapted so as to be switched into action and electrically energized separately or con-jointly, each relay being actuated by a corresponding photo-electric cell unit 12 which was excited by one of the light rays from the correspondingly located light source 11 falling upon it when an appropriately placed transparent signal 2 on the moving positive film passes between the light source inside the hollow sprocket. drum and the preselected photo-electric cell unit 12.

During operation of the projector the opaque strips 3 of the film 1 passes between the exciting lamps It and photo-cells l2 and those portions which are transparent as at 2 permit the light rays from the exciting lamps to be directed upon the photo-cell units 12 which energizes the corresponding circuits to the relays and power relays. The relay circuits include a source of electrical energy such as the 220 volt source indicated on the drawing. The sound amplifier for the speaker units 5 to 3 inclusive has its input connected to the pick-up unit presented to the sound track of the picture strip 1 and the output of the sound amplifier is connected to the speaker units 5 to 8 inclusive and said circuit includes normally open switches which are adapted to be closed upon energization of the power relays S.

I claim:

1. In a sound reproducing system for motion picture projectors employing a picture film strip of normal dimensions having a single sound track along one side thereof, a series of transversely extending opaque potions arranged between the picture frames of said strip provided with a series of laterally spaced signal areas said opaque portions extending along the entire width of the picture frames, a single sound reproducing output circuit adapted to be energized by said sound track, a plurality of loud speaker units connected to said circuit, selector switch means in said output circuit for individually and collectively connecting said loud speaiter unit in said output circuit, electro-magneticmeans for controlling said selective switch means and electro-magnctic control circuits for said electro-magnetic means adapted to be energized when certain of said signal areas move into registry with control means in said electro-magnetic circuit.

2. In a sound reproducing system for motion picture projectors employing a picture film strip having a single sound track along one edge, comprising a series of opaque transversely extending portions between the picture frames of said strip having laterally spaced transparent portions adapted to permit the passage of a signal light beam, said opaque portions extending along the entire width of the picture frames, a sound reproducing output circuit cooperating with said sound track, a series of loud speaker units, electro-magnetic switch means for individually and collectively connecting said loud speaker units into said sound reproducing output circuit, selective control circuits including an electro-magnet for controlling said electro-magnetic switch means and adapted to be energized upon the passage of a light beam through said transparent areas in the opaque portions of said picture strip.

In a sound reproducing system for motion picture projectors employing a picture film strip having a single sound track along one edge thereof comprising a series of transversely extending opaque portions on said strip arranged between the picture frames thereof and being provided with a series of laterally spaced light passageways arranged to move in front of a light source, said opaque portions extending along the entire width of the picture frames, a single sound reproducing output circuit adapted to receive vibrations from said sound track, a plurality of loud speaker units, electro-magnetic switch means for selectively connecting said loud speaker units to said output circuit, an electro-magnetic circuit for each of said switch means including an electro-magnet, and means responsive to the passage of light through at least one of said light passageways to energize a corresponding electro-magnet and connect said loud speaker units to said output circuit.

4. In a sound reproducing system for motion picture projectors employing a picture strip having a single sound track along one edge thereof, comprising a series of transversely arranged opaque portions between said picture frames on said strip having transparent laterally spaced areas adapted to permit the passage of a light beam during passage of said strip in front of alight source, said opaque portions extending along the entire width of the picture frames, a sound reproducing output circuit adapted to receive impulses from said sound track, a series of loud speaker units, electromagnetic switch means in said circuit for individually and collectively connecting said loud speakers to said output circuit, electro-magnetic circuits for each of said switch means including an electro-magnct and a photo-cell positioned to receive light passing through one or more of said transparent areas whereby cncrgization of said electro-magncts will selectively conncct said loud speaker units to said sound reproducing output circuit.

References Cited in the file of this patent UNITED STATES PATENTS 1,793,772 Bouma Feb. 24, 1931 2,022,665 Halstead Dec. 3, 1935 2,207,249 Goldsmith July 9, 1940 2,655,564 Holt-Seeland Oct. 13, 1953 2,822,429 Watson Feb. 4, 1958 FOREIGN PATENTS 342,284 Great Britain Mar. 20, 1929 

